The present invention relates generally to organic chemistry, biochemistry, pharmacology and medicine. More particularly, it relates to tricyclic quinoxaline compounds, and their physiologically acceptable salts and prodrugs, which modulate the activity of protein tyrosine kinases (xe2x80x9cPTKsxe2x80x9d) and, therefore, are expected to exhibit a salutary effect against disorders related to abnormal PTK activity.
The following is offered as background information only and is not admitted to be prior art to the present invention.
Protein kinases, PKs, are enzymes that catalyze the phosphorylation of hydroxy groups on tyrosine, serine and threonine residues of proteins. The consequences of this seemingly simple activity are staggering; cell growth, differentiation and proliferation; i.e., virtually all aspects of cell life in one way or another depend on PK activity. Furthermore, abnormal PK activity has been related to a host of disorders, ranging from relatively non-life threatening diseases such as psoriasis to extremely virulent diseases such as glioblastoma (brain cancer).
The PKs can conveniently be broken down into two classes, the protein tyrosine kinases (PTKs) and the serine-threonine kinases (STKs).
One of the prime aspects of PK activity is involvement with growth factor receptors. Growth factor receptors are cell-surface proteins. When bound by a growth factor ligand, growth factor receptors are converted to an active form which interacts with proteins on the inner surface of a cell membrane. This leads to phosphorylation on tyrosine residues of the receptor and other proteins and to the formation inside the cell of complexes with a variety of cytoplasmic signaling molecules that, in turn, affect numerous cellular responses such as cell division (proliferation), cell differentiation, cell growth, expression of metabolic effects on the extracellular microenvironment, etc. For a more complete discussion, see Schlessinger and Ullrich, Neuron, 9:303-391 (1992) which is incorporated by reference, including any drawings, as if fully set forth herein.
Growth factor receptors with PK activity are known as receptor tyrosine kinases (xe2x80x9cRTKsxe2x80x9d). They comprise a large family of transmembrane receptors with diverse biological activity. At present, at least nineteen (19) distinct subfamilies of RTKs have been identified. An example of these is the subfamily designated the xe2x80x9cHERxe2x80x9d RTKs, which include EGFR (epithelial growth factor receptor), HER2, HER3 and HER4. These RTKs consist of an extracellular glycosylated ligand binding domain, a transmembrane domain and an intracellular cytoplasmic catalytic domain that can phosphorylate tyrosine residues on proteins.
Another RTK subfamily consists of insulin receptor (IR), insulin-like growth factor I receptor (IGF-1R) and the insulin receptor related receptor (IRR). IR and IGF-1R interact with insulin, IGF-I and IGF-II to form a heterotetramer of two entirely extracellular glycosylated xcex1 subunits and two xcex2 subunits which cross the cell membrane and which contain the tyrosine kinase domain.
A third RTK subfamily is referred to as the platelet derived growth factor receptor (xe2x80x9cPDGFRxe2x80x9d) group, which includes PDGFRxcex1, PDGFRxcex2, CSFIR, c-kit and c-fms. These receptors consist of glycosylated extracellular domains composed of variable numbers of immunoglobin-like loops and an intracellular domain wherein the tyrosine kinase domain is interrupted by unrelated amino acid sequences.
Another group which, because of its similarity to the PDGFR subfamily, is sometimes subsumed in the latter group is the fetus liver kinase (xe2x80x9cflkxe2x80x9d) receptor subfamily. This group is believed to be composed of kinase insert domain-receptor fetal liver kinase-1 (KDR/FLK-1), flk-1R, flk-4 and fms-like tyrosine kinase 1 (flt-1).
One further member of the tyrosine kinase growth factor receptor family is the fibroblast growth factor (xe2x80x9cFGFxe2x80x9d)receptor group. This group consists of four receptors, FGFR1-4, and seven ligands, FGF1-7. While not yet well characterized, it appears that the receptors consist of a glycosylated extracellular domain containing a variable number of immunoglobin-like loops and an intracellular domain in which the PTK sequence is interrupted by regions of unrelated amino acid sequences.
A more complete listing of the known RTK subfamilies is described in Plowman et al., DNandP, 7(6):334-339 (1994) which is incorporated by reference, including any drawings, as if fully set forth herein.
In addition to the RTKs, there also exists a family of entirely intracellular PTKs called xe2x80x9cnon-receptor tyrosine kinasesxe2x80x9d or xe2x80x9ccellular tyrosine kinases.xe2x80x9d This latter designation, abbreviated xe2x80x9cCTKxe2x80x9d, will be used herein. CTKs do not contain extracellular and transmembrane domains. At present, over 24 CTKs in 11 subfamilies (Src, Frk, Btk, Csk, Abl, Zap70, Fes, Fps, Fak, Jak and Ack) have been identified. The Src subfamily appear so far to be the largest group of CTKs and includes Src, Yes, Fyn, Lyn, Lck, Blk, Hck, Fgr and Yrk. For a more detailed discussion of CTKs, see Bolen, Oncogene, 8:2025-2031 (1993), which is incorporated by reference, including any drawings, as if fully set forth herein.
The serine-threonine kinases or STKs, like the CTKs, are predominantly intracellular although there are a few receptor STKs. STKs are the most common of the cytosolic kinases; i.e., kinases which perform their function in that part of the cytoplasm other than the cytoplasmic organelles and cytoskelton. The cytosol is the region within the cell where much of the cell""s intermediary metabolic and biosynthetic activity occurs; e.g., it is in the cytosol that proteins are synthesized on ribosomes.
RTKs, CTKs and STKs have all been implicated in a host of pathogenic conditions including, significantly, cancer. Others pathogenic conditions which have been associated with PTKs include, without limitation, psoriasis, hepatic cirrhosis, diabetes, atherosclerosis, angiogenesis, restenosis, ocular diseases, rheumatoid arthritis and other inflammatory disorders, autoimmune disease and a variety of renal disorders.
With regard to cancer, two of the major hypotheses advanced to explain the excessive cellular proliferation that drives tumor development relate to functions known to be PK regulated. That is, it has been suggested that malignant cell growth results from a breakdown in the mechanisms that control cell division and/or differentiation. It has been shown that the protein products of a number of proto-oncogenes are involved in the signal transduction pathways that regulate cell growth and differentiation. These protein products of proto-oncogenes include the extracellular growth factors, transmembrane growth factor PTK receptors (RTKs), cytoplasmic PTKs (CTKs) and cytosolic STKs, discussed above.
In view of the apparent link between PK-related cellular activities and a number of human disorders, it is no surprise that a great deal of effort is being spent in an attempt to identify ways to modulate PK activity. Some of these efforts have involved biomimetic approaches using large molecules patterned after those involved in the actual cellular processes (e.g., mutant ligands (U.S. Pat. No. 4,966,849); soluble receptors and antibodies (App. No. WO 94/10202, Kendall and Thomas, Proc. Nat""l Acad. Sci., 90:10705-09 (1994), Kim, et al., Nature, 362:841-844 (1993)); RNA ligands (Jelinek, et al., Biochemistry, 33:10450-56); Takano, et al., Mol. Bio. Cell 4:358A (1993); Kinsella, et al., Exp. Cell Res. 199:56-62 (1992); Wright, et al., J. Cellular Phys., 152:448-57) and tyrosine kinase inhibitors (WO 94/03427; WO 92/21660; WO 91/15495; WO 94/14808; U.S. Pat. No. 5,330,992; Mariani, et al., Proc. Am. Assoc. Cancer Res., 35:2268 (1994)).
More recently, attempts have been made to identify small molecules which act as PK inhibitors. For example, bis-monocylic, bicyclic and heterocyclic aryl compounds (PCT WO 92/20642), vinylene-azaindole derivatives (PCT WO 94/14808) and 1-cyclopropyl-4-pyridylquinolones (U.S. Pat. No. 5,330,992) have been described as PTK inhibitors. Styryl compounds (U.S. Pat. No. 5,217,999), styryl-substituted pyridyl compounds (U.S. Pat. No. 5,302,606), quinazoline derivatives (EP App. No. 0 566 266 A1), selenaindoles and selenides (PCT WO 94/03427), tricyclic polyhydroxylic compounds (PCT WO 92/21660) and benzylphosphonic acid compounds (PCT WO 91/15495) have all been described as PTK inhibitors useful in the treatment of cancer.
Our own efforts to identify small organic molecules which modulate PK activity and which, therefore, would be expected to be useful in the treatment or prevention of disorders driven by abnormal PK activity, has led us to the discovery of a family of tricyclic quinoxaline compounds which exhibit such PK-modulating activity and which are the subject of this invention.
Thus, the present invention relates generally to tricyclic quinoxaline derivatives which modulate the activity of both receptor (RTK) and non-receptor (CTK) protein tyrosine kinases (PTKs). In addition, the present invention relates to the preparation and use of pharmacological compositions of the disclosed compounds and their physiologically acceptable salts and prodrugs in the treatment or prevention of PTK driven disorders such as, by way of example and not limitation, cancer, diabetes, hepatic cirrhosis, atherosclerosis, angiogenesis and renal disease.
As used herein a xe2x80x9ctricyclic quinoxaline derivativexe2x80x9d refers to a chemical compound having the general structure shown in Formula 1.
A xe2x80x9cpharmacological compositionxe2x80x9d refers to a mixture of one or more of the compounds described herein, or physiologically acceptable salts or prodrugs thereof, with other chemical components such as physiologically acceptable carriers and excipients. The purpose of a pharmacological composition is to facilitate administration of a compound to an organism.
A xe2x80x9cprodrugxe2x80x9d refers to an agent which is converted into the parent drug in vivo. Prodrugs are often useful because, in some situations, they may be easier to administer than the parent drug. They may, for instance, be bioavailable by oral administration whereas the parent drug is not. The prodrug may also have improved solubility compared to the parent drug in pharmacological compositions. An example, without limitation, of a prodrug would be a compound of the present invention which is administered as an ester (the xe2x80x9cprodrugxe2x80x9d) to facilitate transmittal across a cell membrane where water solubility is not beneficial, but which then is metabolically hydrolyzed to the carboxylic acid once inside the cell where water solubility is beneficial.
As used herein, an xe2x80x9cesterxe2x80x9d is a carboxy group, as defined herein, wherein Rxe2x80x3 is any of the listed groups other than hydrogen.
As used herein, a xe2x80x9cphysiologically acceptable carrierxe2x80x9d refers to a carrier or diluent that does not cause significant irritation to an organism and does not abrogate the biological activity and properties of the administered compound.
An xe2x80x9cexcipientxe2x80x9d refers to an inert substance added to a pharmacological composition to further facilitate administration of a compound. Examples, without limitation, of excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives, gelatin, vegetable oils and polyethylene glycols.
1. THE COMPOUNDS
A. General Structural Features.
In one aspect, the present invention relates to compounds having the structure shown in Formula 1: 
The dotted line in the five-member ring containing A, B and D means that either the A-B bond or the B-D bond is a double bond.
A, B, and D are independently selected from the group consisting of carbon, nitrogen, oxygen and sulfur, such that the resulting fused 5-member ring/6-member ring is one known in the chemical arts. It is understood that when A, B or D is oxygen or sulfur, R1, R2 and R3, respectively, do not exist. Furthermore, when A, B or D is nitrogen and that nitrogen is participating in a double bond, R1, R2 or R3, respectively, does not exist.
When A, B or D is nitrogen and that nitrogen is not participating in a double bond, R1, R2 or R3 is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, hydroxy, alkoxy, C-carboxy, O-carboxy, carbonyl, thiocarbonyl, C-amido, guanyl, sulfonyl and trihalomethylsulfonyl.
R4, R5, R6 and R7 are independently selected from the group consisting of hydrogen, alkyl, trihaloalkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, heteroalicyclic, hydroxy, alkoxy, aryloxy, thiohydroxy, thioalkoxy, thioaryloxy, sulfinyl, sulfonyl, N-sulfonamido, S-sulfonamido, trihalomethane-sulfonamido, carbonyl, thiocarbonyl, C-carboxy, O-carboxy, C-amido, N-amido, cyano, nitro, halo, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, ureido, guanyl, guanidino, amino, and xe2x80x94NR10R11, with the proviso that, when one of R5 or R6 is hydrogen, methyl or phenyl, the other is not any of hydrogen, methyl or phenyl.
R10 and R11 are independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, carbonyl, sulfonyl and, combined, a five- or six-member heteroalicyclic ring.
Physiologically acceptable salts and prodrugs of the claimed compounds are also within the scope of this invention.
Examples of a xe2x80x9cfused 5-member ring/6-member ring known in the chemical artsxe2x80x9d include, but are not limited to: 
As used herein, to xe2x80x9cparticipate in a double bondxe2x80x9d means to be one of two atoms which are double-bonded to one another.
As used herein, the term xe2x80x9calkylxe2x80x9d refers to a saturated aliphatic hydrocarbon including straight chain and branched chain groups. Preferably, the alkyl group has 1 to 20 carbon atoms (whenever a numerical range; e.g. xe2x80x9c1-20xe2x80x9d, is stated herein, it means that the group, in this case the alkyl group, may contain 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc. up to and including 20 carbon atoms). More preferably, it is a medium size alkyl having 1 to 10 carbon atoms. Most preferably, it is a lower alkyl having 1 to 4 carbon atoms. The alkyl group may be substituted or unsubstituted. When substituted, the substituent group is preferably one or more independently selected from cycloalkyl, aryl, heteroaryl, heteroalicyclic, hydroxy, alkoxy, aryloxy, thiohydroxy, thioalkoxy, thioaryloxy, cyano, halo, carbonyl, thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, C-carboxy, O-carboxy, nitro, sulfonamido, trihalomethanesulfonamido, silyl, guanyl, guanidino, ureido, amino and NR10R11, wherein R10 and R11 are independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, carbonyl, sulfonyl, trihalomethysulfonyl and, combined, a five- or six-member heteroalicyclic ring.
A xe2x80x9ccycloalkylxe2x80x9d group refers to an all-carbon monocyclic or fused ring (i.e., rings which share an adjacent pair of carbon atoms) group wherein one of more of the rings does not have a completely conjugated pi-electron system. Examples, without limitation, of cycloalkyl groups are cyclopropane, cyclobutane, cyclopentane, cyclopentene, cyclohexane, cyclohexadiene, cycloheptane, cycloheptatriene and adamantane. A cycloalkyl group may be substituted or unsubstituted. When substituted, the substituent group(s) is preferably one or more independently selected from alkyl, aryl, heteroaryl, heteroalycyclic, hydroxy, alkoxy, aryloxy, thiohydroxy, thioalkoxy, thioaryloxy, cyano, halo, carbonyl, thiocarbonyl, C-carboxy, O-carboxy, O-carbamyl, N-carbamyl, C-amido, N-amido, nitro, amino and NR10R11, with R10 and R11 being as defined above.
An xe2x80x9calkenylxe2x80x9d group refers to an alkyl group which consists of at least two carbon atoms and at least one carbon-carbon double bond.
An xe2x80x9calkynylxe2x80x9d group refers to an alkyl group which consists of at least two carbon atoms and at least one carbon-carbon triple bond.
An xe2x80x9carylxe2x80x9d group refers to an all-carbon monocyclic or fused-ring polycyclic (i.e., rings which share adjacent pairs of carbon atoms) groups having a completely conjugated pi-electron system. Examples, without limitation, of aryl groups are phenyl, naphthalenyl and anthracenyl. The aryl group may be substituted or unsubstituted. When substituted, the substituent group is preferably one or more selected from halo, trihalomethyl, alkyl, hydroxy, alkoxy, aryloxy, thiohydroxy, thioalkoxy, thioaryloxy, cyano, nitro, azido, carbonyl, thiocarbonyl, C-carboxy, O-carboxy, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, sulfinyl, sulfonyl, amino and NR10R11 wherein R10 and R11 are previously defined herein.
As used herein, a xe2x80x9cheteroarylxe2x80x9d group refers to a monocyclic or fused ring (i.e., rings which share an adjacent pair of atoms) group having in the ring(s) one or more atoms selected from the group consisting of nitrogen, oxygen and sulfur and, in addition, having a completely conjugated pi-electron system. Examples, without limitation, of heteroaryl groups are pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine, quinoline, isoquinoline and purine. The heteroaryl group may be substituted or unsubstituted. When substituted, the substituted group is preferably one or more selected from alkyl, cycloalkyl, halo, trihalomethyl, hydroxy, alkoxy, aryloxy, thiohydroxy, thioalkoxy, thioaryloxy, cyano, azido, nitro, carbonyl, thiocarbonyl, sulfonamido, C-carboxy, O-carboxy, sulfinyl, sulfonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, amino and NR10R11 where R10 and R11 are previously defined herein.
A xe2x80x9cheteroalicyclicxe2x80x9d group refers to a monocyclic or fused ring group having in the ring(s) one or more atoms selected from the group consisting of nitrogen, oxygen and sulfur. The rings may also have one or more double bonds. However, the rings do not have a completely conjugated pi-electron system. The heteroalicyclic ring may be substituted or unsubstituted. When substituted, the substituted group(s) is preferably one or more selected from alkyl, cycloaklyl, aryl, heteroaryl, halo, trihalomethyl, hydroxy, alkoxy, aryloxy, thiohydroxy, thioalkoxy, thioaryloxy, cyano, nitro, carbonyl, thiocarbonyl, C-carboxy, O-carboxy, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, sulfinyl, sulfonyl, C-amido, N-amido, amino and NR10R11 where R10 and R11 are previously defined herein.
A xe2x80x9chydroxyxe2x80x9d group refers to an xe2x80x94OH group.
An xe2x80x9cazidoxe2x80x9d group refers to a xe2x80x94Nxe2x89xa1N group.
An xe2x80x9calkoxyxe2x80x9d group refers to both an xe2x80x94O-alkyl and an xe2x80x94O-cycloalkyl group, as defined herein.
An xe2x80x9caryloxyxe2x80x9d group refers to both an xe2x80x94O-aryl and an xe2x80x94O-heteroaryl group, as defined herein.
A xe2x80x9cthiohydroxyxe2x80x9d group refers to an xe2x80x94SH group.
A xe2x80x9cthioalkoxyxe2x80x9d group refers to both an S-alkyl and an xe2x80x94S-cycloalkyl group, as defined herein.
A xe2x80x9cthioaryloxyxe2x80x9d group refers to both an xe2x80x94S-aryl and an xe2x80x94S-heteroaryl group, as defined herein.
A xe2x80x9ccarbonylxe2x80x9d group refers to a xe2x80x94C(xe2x95x90O)xe2x80x94Rxe2x80x3 group, where Rxe2x80x3 is selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, heteroaryl (bonded through a ring carbon) and heteroalicyclic (bonded through a ring carbon), as defined herein.
An xe2x80x9caldehydexe2x80x9d group refers to a carbonyl group where Rxe2x80x3 is hydrogen.
A xe2x80x9cthiocarbonylxe2x80x9d group refers to a xe2x80x94C(xe2x95x90S)xe2x80x94Rxe2x80x3 group, with Rxe2x80x3 as defined herein.
A xe2x80x9cC-carboxyxe2x80x9d group refers to a xe2x80x94C(xe2x95x90O)Oxe2x80x94Rxe2x80x3 groups, with Rxe2x80x3 as defined herein.
An xe2x80x9cO-carboxyxe2x80x9d group refers to a Rxe2x80x3C(xe2x95x90O)Oxe2x80x94 group, with Rxe2x80x3 as defined herein.
A xe2x80x9ccarboxylic acidxe2x80x9d group refers to a C-carboxyl group in which Rxe2x80x3 is hydrogen.
A xe2x80x9chaloxe2x80x9d group refers to fluorine, chlorine, bromine or iodine.
A xe2x80x9ctrihalomethylxe2x80x9d group refers to a xe2x80x94CX3 group wherein X is a halo group as defined herein.
A xe2x80x9ctrihalomethanesulfonylxe2x80x9d group refers to a X3CS(xe2x95x90O)2xe2x80x94 groups with X as defined above.
A xe2x80x9csulfinylxe2x80x9d group refers to a xe2x80x94S(xe2x95x90O)xe2x80x94Rxe2x80x3 group, with Rxe2x80x3 as defined herein.
A xe2x80x9csulfonylxe2x80x9d group refers to a xe2x80x94S(xe2x95x90O)2Rxe2x80x3 group, with Rxe2x80x3 as defined herein.
An xe2x80x9cS-sulfonamidoxe2x80x9d group refers to a xe2x80x94S(xe2x95x90O)2NR10R11 group, with R10 and R11 as defined herein.
An xe2x80x9cN-sulfonamidoxe2x80x9d group refers to a R10(xe2x95x90O)2NR11xe2x80x94 group, with R10 and R11 as defined herein.
A xe2x80x9ctrihalomethanesulfonamidoxe2x80x9d group refers to a X3CS(xe2x95x90O)2NR10xe2x80x94 group with R10 as defined herein.
An xe2x80x9cO-carbamylxe2x80x9d group refers to a xe2x80x94OC(xe2x95x90O)NR10R11 group with R10 and R11 as defined herein.
An xe2x80x9cN-carbamylxe2x80x9d group refers to a R11OC(xe2x95x90O)NR10xe2x80x94 group, with R10 and R11 as defined herein.
An xe2x80x9cO-thiocarbamylxe2x80x9d group refers to a xe2x80x94OC(xe2x95x90S)NR10R11 group with R10 and R11 as defined herein.
An xe2x80x9cN-thiocarbamylxe2x80x9d group refers to a R11OC(xe2x95x90S)NR10xe2x80x94 group, with R10 and R11 as defined herein.
An xe2x80x9caminoxe2x80x9d, group refers to an xe2x80x94NH2 group.
A xe2x80x9cC-amidoxe2x80x9d group refers to a xe2x80x94C(xe2x95x90O)NR10R11 group with R10 and R11 as defined herein.
An xe2x80x9cN-amidoxe2x80x9d group refers to a R11C(xe2x95x90O)NR10xe2x80x94 group, with R10 and R11 as defined herein.
A xe2x80x9cquaternary ammoniumxe2x80x9d group refers to a xe2x80x94+NHR10R11 group wherein R10 and R11 are independently selected from the group consisting of alkyl, cycloalkyl, aryl, and heteroaryl.
A xe2x80x9cureidoxe2x80x9d group refers to a xe2x80x94NR10C(xe2x95x90O)NR11R12 group, with R10 and R11 as defined herein and R12 defined the same as R10 and R11.
A xe2x80x9cguanidinoxe2x80x9d group refers to a xe2x80x94R10NC(xe2x95x90N)NR11R12 group, with R10, R11 and R12 as defined herein.
A xe2x80x9cguanylxe2x80x9d group refers to a R10R11NC(xe2x95x90N)xe2x80x94 group, with R10 and R11 as defined herein.
A xe2x80x9cnitroxe2x80x9d group refers to a xe2x80x94NO2 group.
A xe2x80x9ccyanoxe2x80x9d group refers to a xe2x80x94Cxe2x89xa1N group.
A xe2x80x9csilylxe2x80x9d group refers to a xe2x80x94Si(Rxe2x80x3)3, with Rxe2x80x3 as defined herein.
B. Preferred Structural Features.
Preferred structural features of this invention are those in which:
A and D are nitrogen, B is carbon and either A or D is participating in a double bond.
The xe2x80x9cRxe2x80x9d group bonded to whichever of A or D is not participating in a double bond; i.e., R1 or R3, is selected from the group consisting of hydrogen, alkyl, halo, cycloalkyl, aryl, carbonyl and C-carboxy.
R2 is selected from the group consisting of hydrogen, alkyl, cycloalkyl, trihalomethyl, aryl, hydroxy, alkoxy, aryloxy, O-carboxy, amino and NR10R11 where R10 and R11 are independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, carbonyl, sulfonyl, trihalomethanesulfonyl and, combined, a five- or six-member heteroalicyclic ring.
R4 and R7 are independently selected from the group consisting of hydrogen, alkyl, alkoxy, aryloxy, C-carboxy, cycloalkyl, hydroxy and halo.
R5 and R6 are independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, alkoxy, aryl, aryloxy, heteroaryl, heteroalicylic, hydroxy and halo with the proviso that, when one of R5 or R6 is hydrogen, methyl or phenyl, the other is not any of hydrogen, methyl or phenyl.
Further preferred embodiments of this invention are those in which:
A is nitrogen which is participating in a double bond.
D is sulfur.
R2, R4 and R7 are independently selected from the group consisting of hydrogen, alkyl and cycloalkyl.
R5 and R6 are independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, heteroaryl, heteroalicyclic, hydroxy, alkoxy and aryloxy.
Additional preferred embodiments of this invention are those in which:
A is sulfur.
B and D are carbon atoms which are participating in a double bond.
R2 and R3 are independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, C-carboxy and C-amido.
R4 and R7 are independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, hydroxy, alkoxy, aryloxy and carbonyl.
R5 and R6 are independently selected from the group consisting of hydrogen, alkyl, aryl, heteroaryl and heteroalicyclic with the proviso that, when one of R5 or R6 is hydrogen, methyl or phenyl, the other is not any of hydrogen, methyl or phenyl.
The compounds shown in Table 1, infra, comprise still further preferred embodiments of this invention. The substituent designations refer to Formula 1, supra.
2. THE BIOCHEMISTRY
In yet another embodiment, this invention relates to a method for the modulation of the catalytic activity of PTKs comprising administering a compound of this invention or a physiologically acceptable salt or a prodrug thereof to a PTK.
By xe2x80x9cPTKxe2x80x9d is meant both RTKs and CTKs; i.e., the modulation of both RTK signal transduction and CTK signal transduction is contemplated by this invention.
The term xe2x80x9cmethodxe2x80x9d refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts.
As used herein, the term xe2x80x9cmodulationxe2x80x9d or xe2x80x9cmodulatingxe2x80x9d refers to the alteration of the catalytic activity of RTKs and/or CTKs. In particular, modulating refers to the activation of the catalytic activity of RTKs and/or CTKs, more preferably to the activation or inhibition of the catalytic activity of RTKs and/or CTKS, depending on the concentration of the compound administered or, more preferably still, to the inhibition of the catalytic activity of RTKs and/or CTKs.
The term xe2x80x9ccatalytic activityxe2x80x9d as used herein refers to the rate of phosphorylation of tyrosine under the influence, direct or indirect, of RTKs and/or CTKs.
The term xe2x80x9cadministeringxe2x80x9d as used herein refers to a method for bringing a compound of this invention and a target PK together in such a manner that the compound can affect the catalytic activity of the PK either directly; i.e., by interacting with the kinase itself, or indirectly; i.e., by interacting with another molecule on which the catalytic activity of the kinase is dependent. As used herein, administration can be accomplished either in vitro, i.e. in a test tube, or in vivo, i.e. in cells or tissues of a living organism. Thus, the PTK mediated disorders which are the object of this invention can be studied, prevented or treated by the methods set forth herein whether the cells or tissues of the organism exist within the organism or outside the organism. Cells existing outside the organism can be maintained or grown in cell culture dishes. In this context, the ability of a particular compound to affect a PTK related disorder can be determined; i.e., the IC50 of the compound, defined below, can be ascertained before the use of the compounds in more complex living organisms is attempted. For cells outside the organism, multiple methods exist, and are well-known to those skilled in the art, to administer compounds including, but not limited to, direct cell microinjection and numerous transmembrane carrier techniques. For cells harbored within a living organism, myriad methods also exist, and are likewise well-known to those skilled in the art, to administer compounds including, but not limited to, oral, parenteral, dermal and aerosol applications.
RTK mediated signal transduction is initiated by extracellular interaction with a specific growth factor (ligand), followed by receptor dimerization, transient stimulation of the intrinsic protein tyrosine kinase activity and phosphorylation. Binding sites are thereby created for intracellular signal transduction molecules and lead to the formation of complexes with a spectrum of cytoplasmic signaling molecules that facilitate the appropriate cellular response (e.g., cell division or metabolic responses to the extracellular microenvironment). See, Schlessinger and Ullrich, 1992, Neuron 9:303-391.
It has been shown that tyrosine phosphorylation sites in growth factor receptors function as high-affinity binding sites for SH2 (src homology) domains of signaling molecules. Fantl et al., 1992, Cell 69:413-423; Songyang et al., 1994, Mol. Cell. Biol. 14:2777-2785); Songyang et al., 1993, Cell 72:767-778; and Koch et al., 1991, Science 252:668-678. Several intracellular substrate proteins that associate with RTKs have been identified. They may be divided into two principal groups: (1) substrates which have a catalytic domain; and (2) substrates which lack such domain but serve as adapters and associate with catalytically active molecules. Songyang et al., 1993, Cell 72:767-778. The specificity of the interactions between receptors and SH2 domains of their substrates is determined by the amino acid residues immediately surrounding the phosphorylated tyrosine residue. Differences in the binding affinities between SH2 domains and the amino acid sequences surrounding the phosphotyrosine residues on particular receptors are consistent with the observed differences in their substrate phosphorylation profiles. Songyang et al., 1993, Cell 72:767-778. These observations suggest that the function of each RTK is determined not only by its pattern of expression and ligand availability but also by the array of downstream signal transduction pathways that are activated by a particular receptor. Thus, phosphorylation provides an important regulatory step which determines the selectivity of signaling pathways recruited by specific growth factor receptors, as well as differentiation factor receptors.
PTK signal transduction results in, among other responses, cell proliferation, differentiation, growth and metabolism. Abnormal cell proliferation may result in a wide array of disorders and diseases, including the development of neoplasia such as carcinoma, sarcoma, leukemia, glioblastoma and hemangioma; psoriasis, arteriosclerosis, arthritis and diabetic retinopathy and other disorders related to uncontrolled angiogenesis and/or vasculogenesis.
A precise understanding of the mechanism by which the compounds of this invention inhibit PTKs is not required in order to practice the present invention. However, while not being bound to any particular mechanism or theory, it is believed that the compounds interact with the amino acids of the catalytic region of PTKS. PTKs typically possess a bi-lobate structure wherein ATP appears to bind in the cleft between the two lobes in a region where the amino acids are conserved among PTKs. Inhibitors of PTKs are believed to bind by non-covalent interactions such as hydrogen bonding, van der Waals forces and ionic interactions in the same general region where the aforesaid ATP binds to the PTKs. More specifically, it is thought that the quinoxaline ring component of the compounds of this invention binds in the general space normally occupied by the adenine ring of ATP. Specificity of a particular quinoxaline for a particular PTK may arise as the result of additional interactions between the various substituents on the quinoxaline core and the amino acid domain specific to particular PTKs. That is, different quinoxaline substituents may contribute to preferential binding to particular PTKS. The ability to select compounds active at different ATP (or other nucleotide) binding sites makes the compounds of this invention useful for targeting any protein with such a site; i.e., not only PTKs but serine/threonine kinases and protein phosphatases as well. Thus, the compounds disclosed herein may be useful as in vitro assays for such proteins as well as in vivo therapeutic agents acting through such proteins.
Thus, in another aspect, this invention relates to a method for treating or preventing a PTK related disorder by administering a therapeutically effective amount of a compound of this invention or a salt or a prodrug thereof to an organism.
In addition to the compounds described above, the compounds shown in Table 2, below, are expected to be useful in treating or preventing PTK related disorders in an organism.
As used herein, xe2x80x9cPTK related disorder,xe2x80x9d xe2x80x9cPTK driven disorder,xe2x80x9d and xe2x80x9cabnormal PTK activityxe2x80x9d all refer to a disorder characterized by inappropriate PTK activity or over-activity of the PTK, which can be either an RTK or a CTK. Inappropriate activity refers to either: (1) PTK expression in cells which normally do not express PTKs; (2) increased PTK expression leading to unwanted cell proliferation, differentiation and/or growth; or, (3) decreased PTK expression leading to unwanted reductions in cell proliferation, differentiation and/or growth. Overactivity of PTKs refers to either amplification of the gene encoding a particular PTK or production of a level of PTK activity which can correlate with a cell proliferation, differentiation and/or growth disorder (that is, as the level of the PTK increases, the severity of one or more of the symptoms of the cellular disorder increases).
As used herein, the terms xe2x80x9cpreventxe2x80x9d, xe2x80x9cpreventingxe2x80x9d and xe2x80x9cpreventionxe2x80x9d refer to a method for barring an organism from acquiring a PTK mediated cellular disorder in the first place.
As used herein, the terms xe2x80x9ctreatxe2x80x9d, xe2x80x9ctreatingxe2x80x9d and xe2x80x9ctreatmentxe2x80x9d refer to a method of alleviating or abrogating the PTK mediated cellular disorder and/or its attendant symptoms. With regard particularly to cancer, these terms simply mean that the life expectancy of an individual affected with a cancer will be increased or that one or more of the symptoms of the disease will be reduced.
As used herein, the term xe2x80x9ccancerxe2x80x9d refers to various types of malignant neoplasms, most of which can invade surrounding tissues, and may metastasize to different sites, as defined by Stedman""s Medical Dictionary 25th edition (Hensyl ed. 1990). Examples of cancers which may be treated by the present invention include, but are not limited to, brain, ovarian, colon, prostate, kidney, bladder, breast, lung, oral and skin cancers which exhibit inappropriate PTK activity. These cancers can be further broken down. For example, brain cancers include glioblastoma multiforme, anaplastic astrocytoma, astrocytoma, ependymoma, oligodendroglioma, medulloblastoma, meningioma, sarcoma, hemangioblastoma, and pineal parenchymal. Likewise, skin cancers include melanoma and Kaposi""s sarcoma.
The term xe2x80x9corganismxe2x80x9d refers to any living entity comprised of at least one cell. A living organism can be as simple as, for example, a single eukariotic cell or as complex as a mammal, including a human being.
The term xe2x80x9ctherapeutically effective amountxe2x80x9d as used herein refers to that amount of the compound being administered which will relieve to some extent one or more of the symptoms of the disorder being treated. In reference to the treatment of cancer, a therapeutically effective amount refers to that amount which has the effect of (1) reducing the size of the tumor; (2) inhibiting (that is, slowing to some extent, preferably stopping) tumor metastasis; (3) inhibiting to some extent (that is, slowing to some extent, preferably stopping) tumor growth; and/or, (4) relieving to some extent (or preferably eliminating) one or more symptoms associated with the cancer.
This invention is therefore directed to compounds which modulate PTK signal transduction by affecting the enzymatic activity of the RTKs and/or CTKs and thereby interfering with the signal transduced by such proteins. More particularly, the present invention is directed to compounds which modulate the RTK and/or CTK mediated signal transduction pathways as a therapeutic approach to cure many kinds of solid tumors, including but not limited to carcinoma, sarcoma, erythroblastoma, glioblastoma, meningioma, astrocytoma, melanoma and myoblastoma. Indications may include, but are not limited to, brain cancers, bladder cancers, ovarian cancers, gastric cancers, pancreas cancers, colon cancers, blood cancers, lung cancers, bone cancers and leukemias.
Further examples, without limitation, of the types of disorders related to unregulated PTK activity that the compounds described herein may be useful in preventing, treating and studying are cell proliferative disorders, fibrotic disorders and metabolic disorders.
Cell proliferative disorders which may be prevented, treated or further studied by the present invention include cancer, blood vessel proliferative disorders and mesangial cell proliferative disorders.
Blood vessel proliferative disorders refer to angiogenic and vasculogenic disorders generally resulting in abnormal proliferation of blood vessels. The formation and spreading of blood vessels, or vasculogenesis and angiogenesis, respectively, play important roles in a variety of physiological processes such as embryonic development, corpus luteum formation, wound healing and organ regeneration. They also play a pivotal role in cancer development. Other examples of blood vessel proliferation disorders include arthritis, where new capillary blood vessels invade the joint and destroy cartilage, and ocular diseases, like diabetic retinopathy, where new capillaries in the retina invade the vitreous, bleed and cause blindness. Conversely, disorders related to the shrinkage, contraction or closing of blood vessels, such as restenosis, are also implicated.
Fibrotic disorders refer to the abnormal formation of extracellular matrices. Examples of fibrotic disorders include hepatic cirrhosis and mesangial cell proliferative disorders. Hepatic cirrhosis is characterized by the increase in extracellular matrix constituents resulting in the formation of a hepatic scar. Hepatic cirrhosis can lead to diseases such as cirrhosis of the liver. An increased extracellular matrix resulting in a hepatic scar can also be caused by viral infection such as hepatitis. Lipocytes appear to play a major role in hepatic cirrhosis. Other fibrotic disorders implicated include atherosclerosis.
Mesangial cell proliferative disorders refer to disorders brought about by abnormal proliferation of mesangial cells. Mesangial proliferative disorders include various human renal diseases, such as glomerulonephritis, diabetic nephropathy, malignant nephrosclerosis, thrombotic microangiopathy syndromes, transplant rejection, and glomerulopathies. In this regard, PDGFR has been implicated in the maintenance of mesangial cell proliferation. Floege et al., 1993, Kidney International 43:47S-54S.
As noted previously, PTKs have been associated with the development of cancer. Some of these receptors, like EGFR (Tuzi et al., 1991, Br. J. Cancer 63:227-233; Torp et al., 1992, APMIS 100:713-719); HER2/neu (Slamon et al., 1989, Science 244:707-712) and PDGFR (Kumabe et al., 1992, Oncogene, 7:627-633) are over-expressed in many tumors and/or are persistently activated by autocrine loops. In fact, in the most common and severe cancers, such receptor over-expression and autocrine loops have been demonstrated (Akbasak and Suner-Akbasak et al., 1992, J. Neurol. Sci., 111:119-133; Dickson et al., 1992, Cancer Treatment Res. 61:249-273; Korc et al., 1992, J. Clin. Invest. 90:1352-1360); (Lee and Donoghue, 1992, J. Cell. Biol., 118:1057-1070; Korc et al., supra; Akbasak and Suner-Akbasak et al., supra). For example, the EGFR receptor has been associated with squamous cell carcinoma, astrocytoma, glioblastoma, head and neck cancer, lung cancer and bladder cancer. HER2 has been associated with breast, ovarian, gastric, lung, pancreas and bladder cancer. PDGFR has been associated with glioblastoma, melanoma and lung, ovarian, and prostate cancer. The RTK c-met has been generally associated with hepatocarcinogenesis and thus hepatocellular carcinoma. Additionally, c-met has been linked to malignant tumor formation. More specifically, c-met has been associated with, among other cancers, colorectal, thyroid, pancreatic and gastric carcinoma, leukemia and lymphoma. Additionally, over-expression of the c-met gene has been detected in patients with Hodgkins disease and Burkitts disease.
IGF-IR, in addition to being implicated in nutritional support and in type-II diabetes, has also been associated with several types of cancers. For example, IGF-I has been implicated as an autocrine growth stimulator for several tumor types including human breast cancer carcinoma cells (Arteaga et al., 1989, J. Clin. Invest. 84:1418-1423) and small lung tumor cells (Macauley et al., 1990, Cancer Res., 50:2511-2517). In addition, IGF-I, while being integrally involved in the normal growth and differentiation of the nervous system, appears to be an autocrine stimulator of human gliomas. Sandberg-Nordqvist et al., 1993, Cancer Res. 53:2475-2478. The importance of the IGF-IR and its ligands in cell proliferation is further supported by the fact that many cell types in culture (fibroblasts, epithelial cells, smooth muscle cells, T-lymphocytes, myeloid cells, chondrocytes and osteoblasts (the stem cells of the bone marrow)) are stimulated to grow by IGF-I. Goldring and Goldring, 1991, Eukaryotic Gene Expression,1:301-326. In a series of recent publications, Baserga even suggests that IGF-IR plays a central role in the mechanisms of transformation and, as such, could be a preferred target for therapeutic interventions for a broad spectrum of human malignancies. Baserga, 1995, Cancer Res., 55:249-252; Baserga, 1994, Cell 79:927-930; Coppola et al., 1994, Mol. Cell. Biol., 14:4588-4595.
The association between abnormal RTK activity and disease are not restricted to cancer. For example, RTKs have been associated with metabolic diseases like psoriasis, diabetes mellitus, wound healing, inflammation, and neurodegenerative diseases. For example, EGFR has been indicated in corneal and dermal wound healing. Defects in the Insulinxe2x80x94R and IGF-1R are indicated in type-II diabetes mellitus. A more complete correlation between specific RTKs and their therapeutic indications is set forth in Plowman et al., 1994, DNandP 7:334-339.
As noted previously, not only RTKs but CTKs as well including, but not limited to, src, abl, fps, yes, fyn, lyn, lck, blk, hck, fgr and yrk (reviewed by Bolen et al., 1992, FASEB J., 6:3403-3409) are involved in the proliferative and metabolic signal transduction pathway and thus were expected, and have been shown, to be involved in many PTK-mediated disorders to which the present invention is directed. For example, mutated src (v-src) has been demonstrated as an oncoprotein (pp60v-src) in chicken. Moreover, its cellular homolog, the proto-oncogene pp60c-src transmits oncogenic signals of many receptors. Over-expression of EGFR or HER2/neu in tumors leads to the constitutive activation of pp60c-src, which is characteristic for the malignant cell but absent from the normal cell. On the other hand, mice deficient in the expression of c-src exhibit an osteopetrotic phenotype, indicating a key participation of c-src in osteoclast function and a possible involvement in related disorders.
Similarly, Zap70 is implicated in T-cell signaling.
Finally, both RTKs and CTKs are currently suspected as being involved in hyperimmune disorders.
3. PHARMACOLOGICAL COMPOSITIONS AND THERAPEUTIC APPLICATIONS
A compound of the present invention, or its physiologically acceptable salt or prodrug, can be administered to a human patient per se, or in pharmacological compositions where it is mixed with suitable carriers or excipient(s). Techniques for formulation and administration of drugs may be found in xe2x80x9cRemington""s Pharmaceutical Sciences,xe2x80x9d Mack Publishing Co., Easton, Pa., latest edition.
A. Routes Of Administration.
Suitable routes of administration may, for example, include oral, rectal, transmucosal, intestinal or parenteral delivery, including intramuscular, subcutaneous and intramedullary injections as well as intrathecal, direct intraventricular, intravenous, intraperitoneal, intranasal, or intraocular injections.
Alternately, one may administer the compound in a local rather than systemic manner, for example, via injection of the compound directly into a solid tumor, often in a depot or sustained release formulation.
Furthermore, one may administer the drug in a targeted drug delivery system, for example, in a liposome coated with a tumor-specific antibody. The liposomes will be targeted to and taken up selectively by the tumor.
B. Composition/Formulation.
Another aspect of this invention relates to pharmaceutical compositions of the compounds described herein and the physiologically acceptable salts and prodrugs thereof. Pharmacological compositions of the present invention may be manufactured by processes well known in the art; e.g., by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping or lyophilizing processes.
Pharmacological compositions for use in accordance with the present invention thus may be formulated in conventional manner using one or more physiologically acceptable carriers comprising excipients and auxiliaries which facilitate processing of the active compounds into preparations which can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen.
For injection, the compounds of the invention may be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks"" solution, Ringer""s solution, or physiological saline buffer. For transmucosal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art.
For oral administration, the compounds can be formulated readily by combining the active compounds with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to be formulated as tablets, pills, dragees, capsules, liquids, gels, syrups, slurries, suspensions, and the like, for oral ingestion by a patient. Pharmacological preparations for oral use can be made using a solid excipient, optionally grinding the resulting mixture, and processing the mixture of granules, after adding suitable auxiliaries if desired, to obtain tablets or dragee cores. Suitable excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol; cellulose preparations such as, for example, maize starch, wheat starch, rice starch, potato starch, gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose; and/or physiologically acceptable polymers such as polyvinylpyrrolidone (PVP). If desired, disintegrating agents may be added, such as cross-linked polyvinyl pyrrolidone, agar, or alginic acid or a salt thereof such as sodium alginate.
Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, titanium dioxide, lacquer solutions and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses.
Pharmacological compositions which can be used orally include push-fit capsules made of gelatin as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules may contain the active ingredients in admixture with filler such as lactose, binders such as starches, lubricants such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or, suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. In addition, stabilizers may be added. All formulations for oral administration should be in dosages suitable for the chosen route of administration.
For buccal administration, the compositions may take the form of tablets or lozenges formulated in conventional manner.
For administration by inhalation, the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray presentation from a pressurized pack or a nebulizer with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane or carbon dioxide. In the case of a pressurized aerosol, the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges of, e.g., gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.
The compounds described herein may be formulated for parenteral administration, e.g., by bolus injection or continuous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers with, optionally, an added preservative. The compositions may be suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents.
Pharmacological compositions for parenteral administration include aqueous solutions of the active compounds in water soluble form. Additionally, suspensions of the active compounds may be prepared as appropriate oily injection suspensions. Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or synthetic fatty acid esters such as ethyl oleate, triglycerides or liposomes. Aqueous injection suspensions may contain substances which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol or dextran. Optionally, the suspension may also contain suitable stabilizers or agents which increase the solubility of the compounds to allow for the preparation of highly concentrated solutions.
Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g., sterile, pyrogen-free water, before use.
The compounds of this invention may also be formulated in rectal compositions such as suppositories or retention enemas, using, e.g., conventional suppository bases such as cocoa butter or other glycerides.
In addition to the formulations described previously, a compound of this invention may also be formulated as a depot preparation. Such long acting formulations may be administered by implantation (for example subcutaneously or intramuscularly) or by intramuscular injection. Thus, for example, the compounds may be formulated with suitable polymeric or hydrophobic materials (for example, as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives such as sparingly soluble salts.
The pharmacological compositions herein also may comprise suitable solid or gel phase carriers or excipients. Examples of such carriers or excipients include, but are not limited to, calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin and polymers such as polyethylene glycols.
Many of the PTK modulating compounds of the invention may be provided as physiologically acceptable salts wherein the claimed compound may form the negatively or the positively charged species. Examples of salts in which the compound forms the positively charged moiety include, without limitation, quaternary ammonium (defined elsewhere herein), salts such as the hydrochloride, sulfate, carbonate, lactate, tartrate, maleate, succinate, etc. wherein the nitrogen of the quaternary ammonium group is a nitrogen of a compound of this invention which reacts with an appropriate acid. Salts in which the compound forms the negatively charged species include, without limitation, the sodium, potassium, calcium and magnesium salts formed by the reaction of a carboxylic acid group in the molecule with the appropriate base (e.g. sodium hydroxide (NaOH), potassium hydroxide (KOH), Calcium hydroxide (Ca (OH)2) etc.).
C. Dosage.
Pharmacological compositions suitable for use in the present invention include compositions wherein the active ingredients are contained in an amount effective to achieve the intended purpose.
More specifically, a therapeutically effective amount means an amount of compound effective to prevent, alleviate or ameliorate symptoms of disease or prolong the survival of the subject being treated.
Determination of a therapeutically effective amount is well within the capability of those skilled in the art, especially in light of the detailed disclosure provided herein.
For any compound used in the methods of the invention, the therapeutically effective amount or dose can be estimated initially from cell culture assays. For example, a dose can be formulated in animal models to achieve a circulating concentration range that includes the IC50 as determined in cell culture (i.e., the concentration of the test compound which achieves a half-maximal inhibition of the PTK activity). Such information can be used to more accurately determine useful doses in humans.
Toxicity and therapeutic efficacy of the compounds described herein can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., by determining the IC50 and the LD50 (both of which are discussed further, infra) for a subject compound. The data obtained from these cell culture assays and animal studies can be used in formulating a range of dosage for use in human. The dosage may vary depending upon the dosage form employed and the route of administration utilized. The exact formulation, route of administration and dosage can be chosen by the individual physician in view of the patient""s condition. (See e.g., Fingl, et al., 1975, in xe2x80x9cThe Pharmacological Basis of Therapeuticsxe2x80x9d, Ch. 1 p.1).
Dosage amount and interval may be adjusted individually to provide plasma levels of the active moiety which are sufficient to maintain the kinase modulating effects, termed the minimal effective concentration (MEC). The MEC will vary for each compound but can be estimated from in vitro data; e.g., the concentration necessary to achieve 50-90% inhibition of a kinase may be ascertained using the assays described herein. Dosages necessary to achieve the MEC will depend on individual characteristics and route of administration. HPLC assays or bioassays can be used to determine plasma concentrations.
Dosage intervals can also be determined using the MEC value. Compounds should be administered using a regimen which maintains plasma levels above the MEC for 10-90% of the time, preferably between 30-90% and most preferably between 50-90%.
It is noted that, in the case of local administration or selective uptake, the effective local concentration of the drug may not be related to plasma concentration. In such cases, other procedures known in the art can be employed to determine the effective local concentration.
The amount of a composition to be administered will, of course, be dependent on the subject being treated, the severity of the affliction, the manner of administration, the judgment of the prescribing physician, etc.
D. Packaging.
Compositions of the present invention may, if desired, be presented in a pack or dispenser device, such as an FDA approved kit, which may contain one or more unit dosage forms containing the active ingredient. The pack may, for example, comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration. The pack or dispenser may also be accompanied by a notice associated with the container in a form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals, which notice is reflective of approval by the agency of the form of the compositions or human or veterinary administration. Such notice, for example, may be of the labeling approved by the U.S. Food and Drug Administration for prescription drugs or of an approved product insert. Compositions comprising a compound of the invention formulated in a compatible pharmaceutical carrier may also be prepared, placed in an appropriate container, and labeled for treatment of an indicated condition. Suitable conditions indicated on the label may include treatment of a tumor, inhibition of angiogenesis, treatment of fibrosis, diabetes, and the like.
4. BRIEF DESCRIPTION OF THE TABLES.
Table 1 shows the chemical structure of specific compounds of this invention. The compounds shown are not to be construed as limiting the scope of this invention in any manner whatsoever.
Table 2 shows the chemical structures of compounds which are not claimed herein as composition of matter but, rather, are claimed for their expected utility as modulators of PTK activity and for the treatment and prevention of PTK-related disorders.
Table 3 shows the results of biological assays of some compounds of this invention. These results are provided as examples only and are not to be construed as limiting the scope of this invention in any manner including compound structure, the PTK against which the demonstrative compounds show activity or the level of activity (IC50) shown. PDGFR, FLK-1R and EGFR Kinase are defined and discussed elsewhere herein. IC50 refers to that amount of the tested compound needed to effect a 50% change in the activity of the PTK in comparison with a control in which no compound of this invention is present. With regard to the tests in the table, the 50% change being evaluated is a 50% inhibition of PTK activity compared to that in a control.
5. SYNTHESIS
The compounds of this invention may be readily synthesized using techniques well known in the chemical arts. Other synthetic pathways for forming the compounds of the invention will be apparent to those skilled in the art and are deemed to be within the scope and spirit of this invention.